The present invention relates to monitoring and control of small-scale power generators.
Worldwide, the demand for energy continues to increase while the supply of energy, such as electricity, is not always able to keep up with the increased demand. For instance, recently the west coast of the United States has been gripped by an energy crisis as the demand for energy, and more specifically electricity, has increased faster than improvements in infrastructure and capacity. The result of this was most pronounced in California where electricity producing plants have been running at virtually maximum capacity in order to provide electricity to the residents and industry of California. Even running at capacity, there have been rolling brown-outs where entire grids are provided with reduced power for a period of time. In order to remedy this problem, additional electrical power generating plants are required. However, the construction of such a large-scale electrical generating facility takes years to complete and is a very costly process. Thus, there is currently a dire need in many places, such as the west coast of the United States of America, to reduce energy consumption and to increase electrical capacity.
It is somewhat surprising to learn that even while the power plants operating in the western regions of the United States are running at virtually maximum capacity, they have back-up and peak generators that sit idle. These idled generators are used to provide additional electricity during peak demand. Many of these generators cannot be run fulltime because they are powered by fossil fuel engines such as reciprocating diesel engines, reciprocating gas engines, and gas turbines which generally produce relatively large emissions, especially if operated at less than optimal conditions. The United States Environmental Protection Agency (EPA) has promulgated rules such as 40 CFR 60, part 75, that prescribe the maximum emissions that such fossil fuel-based generators can produce. The result of this is that while many parts of the western United States wrestle with dire electrical capacity and demand, thousands of back-up and peak generators in that very region sit idle.
Many large facilities also have their own back-up generators to provide back-up electricity for mission critical processes if their own supply of electricity is interrupted. Examples of such facilities include large corporations, hospitals, water and waste treatment facilities, shopping centers, prisons, universities, and any other facilities where the unit cost of electricity prohibits operation during non-emergency situations. Thus, in such situations, these generators also sit idle. As used herein, generator includes any system that converts any form of energy into electrical energy.
Another group of under-utilized generators can be found at facilities such as fast food restaurants, hotels, and other miscellaneous buildings. Such power systems are not used for back-up but generally run continuously or when the business is operating. However, such generators are typically oversized and their demanded internal use is periodic (higher when temperature is either higher or lower due to heating or air conditioned needs, higher when more people are in the building, and generally not used when the facility is closed). On average, these resources are operated at less than approximately 50 percent capacity. Large-scale deployment of such generators is significantly limited by the lack of a cost-effective Continuous Emission Monitoring System (CEMS) solution and the economics of having to buy a system that is often twice as large as what is required.
There are a number of technical hurdles that must be surmounted before large-scale implementation of available generators can occur. A first issue relates to emissions from fossil fuel burning generators. As described above, current continuous operation of such fossil fuel burning generators is limited due to the lack of a suitable emissions monitoring system. Another challenge that must be surmounted is the large-scale monitoring, control and maintenance of such generators. Further, it is important to improve energy efficiency as much as possible in order to extract as much usable energy as possible from a given source.
With respect to the emissions of fossil fuel based generators, it has been long known that fossil fuel engines such as diesel engines, also known as compression ignition engines, have high exhaust emissions. Emissions include carbon soot, carbon dioxide, volatile organic compounds, hydrocarbons and oxides of nitrogen.
The United States EPA is particularly concerned with emissions of diesel engines and numerous efforts are currently underway to reduce the emissions of such engines. See, for example, U.S. Pat. No. 6,173,567 to Poola et al. Currently, all power generation plants are required to record emissions and allow the EPA to conduct an on-site audit. During the audit, the EPA reviews emission data and typically requests an emission monitor calibration in their presence. To record and demonstrate calibration on each generator is an administrative burden. The cost of outfitting, calibrating and demonstrating each generator is one constraint that has heretofore prohibited effective use of such generators.
Regardless of the methods in which fossil fuel engines are controlled, in order to reduce exhaust emissions therefrom, it is generally necessary to somehow monitor the exhaust emissions themselves to provide a closed-loop system. The EPA does allow diesel peak generators to operate for short periods of time without monitoring of emissions, however this constraint reduces capacity. In electrical power producing plants, Continuous Emission Monitoring Systems (CEMS) are used to continuously sample exhaust emissions and analyze them for constituent components.
Currently, the CEMS equipment used for electrical power producing plants is wholly unsuitable for relatively small-scale generators that sit idle or are underutilized. This is because such current CEMS equipment is extremely unwieldy, often weighing over 300 pounds and requiring special transportation and special handling. Further, typical CEMS sample handling systems require approximately 120 hours of assembly and can cost upwards of $16,000.00. These factors in comparison to the cost and number of individual diesel-electric generators renders current CEMS equipment, though technically feasible, wholly impractical for such smaller applications.
A continuous emission monitoring system for small-scale fossil fuel generator systems that could be easily mounted on such generators and installed for a cost that could be justified, would facilitate enhanced emissions monitoring and use of such electrical generators. Monitoring the operation of the generators would facilitate compliance with current United States Environmental Protection Agency Guidelines, thereby allowing such generators to operate full time if need be. One potential use would be to allow the tens of thousands of smaller scale generators to assist in transition times where large-scale electrical generation plants are under construction. Further, the various corporations employing such generators could produce electricity with such generators and sell their excess electricity back to the energy or utility companies for transmission to others. The advantages provided by these generators will only increase as technical advances are made to reduce the emissions of diesel engines and improve diesel fuels.
As discussed above, management and control of such generators also presents a challenge. Specifically, in order to effectively utilize the capacity provided by such generators, it is important to be able to manage such devices without having to manually monitor and adjust each and every generator during operation to comply with EPA regulations. It is also important to be able to monitor emissions from fossil-fuel based generators without being present at the generator's location, given that such generators may number in the thousands.
Further, the economics of large-scale implementation of such generators and controllers would be improved if the efficiency of such systems could be improved. For example, it would be beneficial if the waste heat flowing from the generator itself could be put to additional use.